/*
 * @(#)TimeAttribute.java
 *
 * Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *   2. Redistribution in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
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 *
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 */

package org.wso2.balana.attr;

import org.wso2.balana.ParsingException;
import org.wso2.balana.ProcessingException;

import java.net.URI;

import java.text.ParseException;

import java.util.Date;

import org.w3c.dom.Node;

/**
 * Representation of an xs:time value. This class supports parsing xs:time
 * values. All objects of this class are immutable and thread-safe. The
 * <code>Date</code> objects returned are not, but these objects are cloned
 * before being returned.
 * 
 * @since 1.0
 * @author Steve Hanna
 * @author Seth Proctor
 */
public class TimeAttribute extends AttributeValue {
	/**
	 * Official name of this type
	 */
	public static final String identifier = "http://www.w3.org/2001/XMLSchema#time";

	/**
	 * URI version of name for this type
	 * <p>
	 * This field is initialized by a static initializer so that we can catch
	 * any exceptions thrown by URI(String) and transform them into a
	 * RuntimeException, since this should never happen but should be reported
	 * properly if it ever does.
	 * <p>
	 * This object is used for synchronization whenever we need protection
	 * across this whole class.
	 */
	private static URI identifierURI;

	/**
	 * RuntimeException that wraps an Exception thrown during the creation of
	 * identifierURI, null if none.
	 */
	private static RuntimeException earlyException;

	/**
	 * Static initializer that initializes the identifierURI class field so that
	 * we can catch any exceptions thrown by URI(String) and transform them into
	 * a RuntimeException. Such exceptions should never happen but should be
	 * reported properly if they ever do.
	 */
	static {
		try {
			identifierURI = new URI(identifier);
		} catch (Exception e) {
			earlyException = new IllegalArgumentException();
			earlyException.initCause(e);
		}
	};

	/**
	 * Time zone value that indicates that the time zone was not specified.
	 */
	public static final int TZ_UNSPECIFIED = -1000000;

	/**
	 * The time that this object represents in second resolution, in
	 * milliseconds GMT, with zero being midnight. If no time zone was
	 * specified, the local time zone is used to convert to milliseconds
	 * relative to GMT.
	 */
	private long timeGMT;

	/**
	 * The number of nanoseconds beyond the time given by the timeGMT field. The
	 * XML Query document says that fractional seconds must be supported down to
	 * at least 100 nanosecond resolution. The Date class only supports
	 * milliseconds, so we include here support for nanosecond resolution.
	 */
	private int nanoseconds;

	// NOTE: now that we're not using a Date object, the above two variables
	// could be condensed, and the interface could be changed so we don't
	// need to worry about tracking the time values separately

	/**
	 * The time zone specified for this object (or TZ_UNSPECIFIED if
	 * unspecified). The offset to GMT, in minutes.
	 */
	private int timeZone;

	/**
	 * The time zone actually used for this object (if it was originally
	 * unspecified, the default time zone used). The offset to GMT, in minutes.
	 */
	private int defaultedTimeZone;

	/**
	 * Cached encoded value (null if not cached yet).
	 */
	private String encodedValue = null;

	/**
	 * Creates a new <code>TimeAttribute</code> that represents the current time
	 * in the current time zone.
	 */
	public TimeAttribute() {
		this(new Date());
	}

	/**
	 * Creates a new <code>TimeAttribute</code> that represents the given time
	 * but uses the default timezone and offset values.
	 * 
	 * @param time
	 *            a <code>Date</code> object representing the specified time
	 *            down to second resolution. This date should have a date of
	 *            01/01/1970. If it does not, such a date will be forced. If
	 *            this object has non-zero milliseconds, they are combined with
	 *            the nanoseconds parameter.
	 */
	public TimeAttribute(Date time) {
		super(identifierURI);

		int currOffset = DateTimeAttribute.getDefaultTZOffset(time);
		init(time, 0, currOffset, currOffset);
	}

	/**
	 * Creates a new <code>TimeAttribute</code> that represents the time
	 * supplied.
	 * 
	 * @param time
	 *            a <code>Date</code> object representing the specified time
	 *            down to second resolution. This date should have a date of
	 *            01/01/1970. If it does not, such a date will be forced. If
	 *            this object has non-zero milliseconds, they are combined with
	 *            the nanoseconds parameter.
	 * @param nanoseconds
	 *            the number of nanoseconds beyond the Date specified in the
	 *            date parameter
	 * @param timeZone
	 *            the time zone specified for this object (or TZ_UNSPECIFIED if
	 *            unspecified). The offset to GMT, in minutes.
	 * @param defaultedTimeZone
	 *            the time zone actually used for this object, which must be
	 *            specified. The offset to GMT, in minutes.
	 */
	public TimeAttribute(Date time, int nanoseconds, int timeZone,
			int defaultedTimeZone) {
		super(identifierURI);

		// if the timezone is unspecified, it's illegal for the defaulted
		// timezone to also be unspecified
		if ((timeZone == TZ_UNSPECIFIED)
				&& (defaultedTimeZone == TZ_UNSPECIFIED))
			throw new ProcessingException("default timezone must be specified"
					+ "when a timezone is provided");

		init(time, nanoseconds, timeZone, defaultedTimeZone);
	}

	/**
	 * Initialization code shared by constructors.
	 * 
	 * @param date
	 *            a <code>Date</code> object representing the specified time
	 *            down to second resolution. This date should have a date of
	 *            01/01/1970. If it does not, such a date will be forced. If
	 *            this object has non-zero milliseconds, they are combined with
	 *            the nanoseconds parameter.
	 * @param nanoseconds
	 *            the number of nanoseconds beyond the Date specified in the
	 *            date parameter
	 * @param timeZone
	 *            the time zone specified for this object (or TZ_UNSPECIFIED if
	 *            unspecified). The offset to GMT, in minutes.
	 * @param defaultedTimeZone
	 *            the time zone actually used for this object (if it was
	 *            originally unspecified, the default time zone used). The
	 *            offset to GMT, in minutes.
	 */
	private void init(Date date, int nanoseconds, int timeZone,
			int defaultedTimeZone) {

		// Shouldn't happen, but just in case...
		if (earlyException != null)
			throw earlyException;

		// get a temporary copy of the date
		Date tmpDate = (Date) (date.clone());

		// Combine the nanoseconds so they are between 0 and 999,999,999
		this.nanoseconds = DateTimeAttribute.combineNanos(tmpDate, nanoseconds);

		// now that the date has been (potentially) updated, store the time
		this.timeGMT = tmpDate.getTime();

		// keep track of the timezone values
		this.timeZone = timeZone;
		this.defaultedTimeZone = defaultedTimeZone;

		// Check that the date is normalized to 1/1/70
		if ((timeGMT >= DateAttribute.MILLIS_PER_DAY) || (timeGMT < 0)) {
			timeGMT = timeGMT % DateAttribute.MILLIS_PER_DAY;

			// if we had a negative value then we need to shift by a day
			if (timeGMT < 0)
				timeGMT += DateAttribute.MILLIS_PER_DAY;
		}
	}

	/**
	 * Returns a new <code>TimeAttribute</code> that represents the xs:time at a
	 * particular DOM node.
	 * 
	 * @param root
	 *            the <code>Node</code> that contains the desired value
	 * @return a new <code>TimeAttribute</code> representing the appropriate
	 *         value (null if there is a parsing error)
	 */
	public static TimeAttribute getInstance(Node root) throws ParsingException,
			NumberFormatException, ParseException {
		return getInstance(root.getFirstChild().getNodeValue());
	}

	/**
	 * Returns a new <code>TimeAttribute</code> that represents the xs:time
	 * value indicated by the string provided.
	 * 
	 * @param value
	 *            a string representing the desired value
	 * @return a new <code>TimeAttribute</code> representing the desired value
	 *         (null if there is a parsing error)
	 * @throws ParsingException
	 *             if any problems occurred while parsing
	 */
	public static TimeAttribute getInstance(String value)
			throws ParsingException, NumberFormatException, ParseException {
		// Prepend date string for Jan 1 1970 and use the
		// DateTimeAttribute parsing code.

		value = "1970-01-01T" + value;

		DateTimeAttribute dateTime = DateTimeAttribute.getInstance(value);

		// if there was no explicit TZ provided, then we want to make sure
		// the that the defaulting is done correctly, especially since 1/1/70
		// is always out of daylight savings time

		Date dateValue = dateTime.getValue();
		int defaultedTimeZone = dateTime.getDefaultedTimeZone();
		if (dateTime.getTimeZone() == TZ_UNSPECIFIED) {
			int newDefTimeZone = DateTimeAttribute
					.getDefaultTZOffset(new Date());
			dateValue = new Date(dateValue.getTime()
					- (newDefTimeZone - defaultedTimeZone)
					* DateAttribute.MILLIS_PER_MINUTE);
			defaultedTimeZone = newDefTimeZone;
		}

		return new TimeAttribute(dateValue, dateTime.getNanoseconds(),
				dateTime.getTimeZone(), defaultedTimeZone);
	}

	/**
	 * Gets the time represented by this object. The return value is a
	 * <code>Date</code> object representing the specified time down to second
	 * resolution with a date of January 1, 1970. Subsecond values are handled
	 * by the {@link #getNanoseconds getNanoseconds} method.
	 * 
	 * @return a <code>Date</code> object representing the time represented by
	 *         this object
	 */
	public Date getValue() {
		return new Date(timeGMT);
	}

	/**
	 * Gets the number of milliseconds since midnight GMT that this attribute
	 * value represents. This is the same time returned by <code>getValue</code>
	 * , and likewise the milliseconds are provided with second resolution.
	 * 
	 * @return milliseconds since midnight GMT
	 */
	public long getMilliseconds() {
		return timeGMT;
	}

	/**
	 * Gets the nanoseconds of this object.
	 * 
	 * @return the number of nanoseconds
	 */
	public int getNanoseconds() {
		return nanoseconds;
	}

	/**
	 * Gets the time zone of this object (or TZ_UNSPECIFIED if unspecified).
	 * 
	 * @return the offset to GMT in minutes (positive or negative)
	 */
	public int getTimeZone() {
		return timeZone;
	}

	/**
	 * Gets the time zone actually used for this object (if it was originally
	 * unspecified, the default time zone used).
	 * 
	 * @return the offset to GMT in minutes (positive or negative)
	 */
	public int getDefaultedTimeZone() {
		return defaultedTimeZone;
	}

	/**
	 * Returns true if the input is an instance of this class and if its value
	 * equals the value contained in this class.
	 * 
	 * @param o
	 *            the object to compare
	 * 
	 * @return true if this object and the input represent the same value
	 */
	public boolean equals(Object o) {
		if (!(o instanceof TimeAttribute))
			return false;

		TimeAttribute other = (TimeAttribute) o;

		return (timeGMT == other.timeGMT && (nanoseconds == other.nanoseconds));
	}

	/**
	 * Returns the hashcode value used to index and compare this object with
	 * others of the same type. Typically this is the hashcode of the backing
	 * data object.
	 * 
	 * @return the object's hashcode value
	 */
	public int hashCode() {
		// the standard Date hashcode is used here...
		int hashCode = (int) (timeGMT ^ (timeGMT >>> 32));

		// ...but both the timeGMT and the nanoseconds fields are considered
		// by the equals method, so it's best if the hashCode is derived
		// from both of those fields.
		hashCode = (31 * hashCode) + nanoseconds;

		return hashCode;
	}

	/**
	 * Converts to a String representation.
	 * 
	 * @return the String representation
	 */
	public String toString() {
		StringBuffer sb = new StringBuffer();
		sb.append("TimeAttribute: [\n");

		// calculate the GMT value of this time
		long secsGMT = timeGMT / 1000;
		long minsGMT = secsGMT / 60;
		secsGMT = secsGMT % 60;
		long hoursGMT = minsGMT / 60;
		minsGMT = minsGMT % 60;

		// put the right number of zeros in place
		String hoursStr = (hoursGMT < 10) ? "0" + hoursGMT : "" + hoursGMT;
		String minsStr = (minsGMT < 10) ? "0" + minsGMT : "" + minsGMT;
		String secsStr = (secsGMT < 10) ? "0" + secsGMT : "" + secsGMT;

		sb.append("  Time GMT: " + hoursStr + ":" + minsStr + ":" + secsStr);
		sb.append("  Nanoseconds: " + nanoseconds);
		sb.append("  TimeZone: " + timeZone);
		sb.append("  Defaulted TimeZone: " + defaultedTimeZone);
		sb.append("]");

		return sb.toString();
	}

	/**
	 * Encodes the value in a form suitable for including in XML data like a
	 * request or an obligation. This returns a time value that could in turn be
	 * used by the factory to create a new instance with the same value.
	 * 
	 * @return a <code>String</code> form of the value
	 */
	public String encode() {
		if (encodedValue != null)
			return encodedValue;

		// "hh:mm:ss.sssssssss+hh:mm".length() = 27
		StringBuffer buf = new StringBuffer(27);

		// get the correct time for the timezone being used
		int millis = (int) timeGMT;
		if (timeZone == TZ_UNSPECIFIED)
			millis += (defaultedTimeZone * DateAttribute.MILLIS_PER_MINUTE);
		else
			millis += (timeZone * DateAttribute.MILLIS_PER_MINUTE);

		if (millis < 0) {
			millis += DateAttribute.MILLIS_PER_DAY;
		} else if (millis >= DateAttribute.MILLIS_PER_DAY) {
			millis -= DateAttribute.MILLIS_PER_DAY;
		}

		// now generate the time string
		int hour = millis / DateAttribute.MILLIS_PER_HOUR;
		millis = millis % DateAttribute.MILLIS_PER_HOUR;
		buf.append(DateAttribute.zeroPadInt(hour, 2));
		buf.append(':');
		int minute = millis / DateAttribute.MILLIS_PER_MINUTE;
		millis = millis % DateAttribute.MILLIS_PER_MINUTE;
		buf.append(DateAttribute.zeroPadInt(minute, 2));
		buf.append(':');
		int second = millis / DateAttribute.MILLIS_PER_SECOND;
		buf.append(DateAttribute.zeroPadInt(second, 2));

		// add any nanoseconds
		if (nanoseconds != 0) {
			buf.append('.');
			buf.append(DateAttribute.zeroPadInt(nanoseconds, 9));
		}

		// if there is a specified timezone, then include that in the encoding
		if (timeZone != TZ_UNSPECIFIED) {
			int tzNoSign = timeZone;
			if (timeZone < 0) {
				tzNoSign = -tzNoSign;
				buf.append('-');
			} else
				buf.append('+');
			int tzHours = tzNoSign / 60;
			buf.append(DateAttribute.zeroPadInt(tzHours, 2));
			buf.append(':');
			int tzMinutes = tzNoSign % 60;
			buf.append(DateAttribute.zeroPadInt(tzMinutes, 2));
		}

		// remember the encoding for later
		encodedValue = buf.toString();

		return encodedValue;
	}

}
